The findings held even after researchers took into account underlying health problems.

The study is published online in the British Journal of Urology International.

Erectile dysfunction is the inability to achieve or maintain an erection suitable for sexual intercourse. It affects as many as 30 million U.S. men, according to the National Institutes of Health.

Exactly how taking multiple medications may increase risk for severe ED is not fully understood. But the findings suggest that tapering off unnecessary medications may be the first step in treating ED in some men.

"If you have difficulty with ED, consider curtailing any OTC medications that you don't need. And then really work with your doctor to see if you can cut down on any of your prescription medications," says study researcher Diana C. Londono, MD. She is a urologist at Kaiser Permanente Los Angeles Medical Center.

There are medications that treat ED, she says, but for these men, the first step is to look at what they are already taking to see if making some tweaks can improve the situation.

Tracking Use of Medication

Researchers tracked information about medication use among 37,712 men aged 45 to 69 years between 2002 and 2003.

Of these men, 29% said they had moderate or severe ED. The more medications the men took, the more likely they were to experience moderate or severe ED, the study showed.

Second Opinion

Joseph P. Alukal, MD, says that the study confirms that men who are sicker and/or are on more medications are more likely to have ED. He is an assistant professor of urology at the New York University School of Medicine.

On the flip side, ED may be an excellent window into someone's overall health.

It's a two-way street, Alukal says. Multiple medications and health problems can suggest ED, but ED can also help identify other related health problems, such as heart disease or diabetes.

"If you are struggling with ED, come in," he says. "We have great treatments that we did not have 10 to 15 years ago. But even more importantly, it can tell us something about your health."